The invention relates to a sealing device for a turbomachine, as it is known, for example, from WO 2009/118490 A2, as well as a turbomachine.
In order to seal a radially inner gas channel between a guide vane ring and a rotor of a turbomachine, such as a gas turbine, and, in particular, an aircraft engine, so-called fish mouth seals are used, for which a peripheral essentially cylindrical rotor ring of a row of rotating blades rotates in an annular sealed space, which is delimited by a radially inner stator ring and a radially outer stator ring of the guide vane ring. Vortexing arises in the sealed space, by means of which a feed of hot gas from the heating gas channel into the inner gas channel will be prevented.
The two stator rings conventionally have very different temperatures, so that the fish mouth seals must be configured in such a way that resulting thermal expansions are kept within an acceptable stress level or are reduced.
Additionally, for sealing the inner gas channel, a flow around the guide vane ring between the row of guide vanes and a rotor drum must be prevented, which is usually effected by a labyrinth seal inside the inner gas channel.
Basically, the following two constructions are known for the formation of fish mouth seals: In a first construction, the inner stator ring is formed integrally with the outer stator ring of the guide vane ring This construction, however, leads not rarely to the formation of cracks in the hot transition region between the stator rings, due to the thermally caused stresses. In a second construction, the inner stator ring is screwed to a front radial flange of the guide vane ring. The second construction in fact displays a better behavior relative to the thermally induced stresses in the fish mouth seal, but creates a potentially large leakage surface due to the contact of the inner stator ring at the guide vane ring.